In container filling machines, a frequent exchange of the centering socket is necessary, when the socket, for example, experiences deterioration or when the container filling machine is changed over to fill a different type of container. In order to conduct transaction rapidly and without difficulty, it has already been proposed to detachable mount the centering socket by means of a manually operated snap ring at the appropriate filling device (DE-AS 1 261 769). This known design is relatively bulky and spacious and does not comply with stricter microbiological requirements.